Corrosion under insulation (CUI) is a particular type of corrosion that can occur in insulated equipment (e.g., piping) due to ingress of water into the insulated layer and moisture build-up on the external surface of the insulated equipment. Insulated equipment that is exposed to mist and cooling water towers, as well as equipment that is exposed to steam vents can be especially vulnerable to the development of CUI. CUI is difficult to detect in its early stages as its precursor is merely the accumulation of moisture and water patches underneath the insulation layers, which is not visible from outside of the equipment. CUI that remains undetected can cause major damage to the equipment and, in severe cases, can even result in the closure of a process unit that features the damaged equipment.
For insulated pipes, the structure of the pipe generally includes several layers, including (starting from the inside and moving outward): a compatible coating, the insulation material, and a metal jacket cladding. The cladding acts as a protective barrier on the outside of the piping, protecting the pipe from the outside elements (e.g., weather). For example, the cladding helps to prevent the insulation from being exposed to rain or physical damages.
Conventionally, in order to inspect insulated equipment for CUI, the portion of the equipment to be inspected is stripped of its cladding and its insulation, and is then visually inspected to see if CUI exists. These current practices, however, are time consuming and costly. Specifically, downtime of the insulated equipment during inspection, replacement of cladding after inspection, and repairs to damaged equipment (e.g., removing damaged insulation) all result in increased costs. Early detection of CUI can limit the damage to the equipment and thus limit the economic effects of the damage; however, early detection of CUI is difficult due to the time-consuming nature of the current inspection processes and the hidden nature of the precursors of CUI. Accordingly, there is a need for a more time-effective and cost-effective process for inspecting insulated equipment for CUI and its precursors. The present invention addresses one or more of these and other needs.